Process of bonding asbestos fibers with a titanium polymer and article produced thereby



United tates PROCESS OF BONDING ASBESTOS FIBERS WITH A TITANIUltIPOLYMER AND ARTICLE PRO- DUCED THEREBY No Drawing. Application October6, 1950, Serial No. 188,879

Claims. (Cl. 117-12s This invention relates to fabricated asbestosfibers of improved wet strength and. to a process for treatingfabricated fibers.

Asbestos fibers in the form of paper, rope, batts, etc. are used asinsulation in numerous applications but have the disadvantage that theybecome seriously weakened when soaked with water. As a result the wetmaterials disintegrate under slight stress and the insulating value islost.

One object of this invention is to provide asbestos fibers having arelatively high wet strength.

A further object is to provide a process for improving the wet strengthof fabricated asbestos fibers.

Still another object is to provide asbestos paper having improved wetstrength.

A still further object is to provide asbestos fibers bonded with awater-insensitive polymeric product derived from a straight-chainpolymer of a tetraorgano derivative of orthotitanic acid.

These and other objects are attained by impregnating fabricated asbestosfibers with an anhydrous organic solvent solution of a straight-chainpolymer of a tetraorgano derivative of orthotitanic acid, removing thesolvent and reacting the straight-chain polymer with water to therebyform a polymeric water-insensitive reaction product.

The following examples are given in illustration and are not intended tolimit the scope of this invention. Where parts are mentioned they areparts by weight.

Example I Untreated Treated Paper Paper 0. 78 5. 34 Across 0.14 1.80

The figures given above are in pounds per inch of width of the testsample and represent averages of five samples for each test. Withindicates that when the sample was tested, the stress was applied in themachine direction of the paper and across indicates that the stress wasapplied at right angles to said direction. In the test, the sample waswet with water and the test was run at 23 C. with the rate of travel ofthe lower clamp in the testing machine set at two inches per minute.

atnit The results show that the dry strength of the asbestos paper issubstantially unaffected by the impregnant but that the wet strength ofthe treated paper is six times greater than that of the untreated paperin one direction and twelve times greater in the other direction.

The impregnated paper was also tested for tear strength with theElmendorf tear tester according to ASTM 13689-44. The following resultsreported in gram-centimeters indicate the work necessary to tear singlesheets of These results indicate that the treated paper has increasedresistance to tearing in both the dry and wet conditions.

The method of this invention comprises impregnating asbestos fibers inpaper, rope, batt, etc. form with av condensation polymer of an organotitanium compound, followed by drying of the impregnated fibers in ahumid atmosphere. Since the polymers are either viscous liquids orsolids, it is necessary to use a dilute solution of the polymer in ananhydrous solvent such as benzene, toluene, xylene, alcohols, etc. forthe impregnation step. The amount of polymer picked up by the paper maybe varied from about 0.5 to about 3% by weight based on the weight ofthe paper.

It is essential that the titanium polymer be in an anhydrous medium whenapplied to the paper and that the impregnated paper be dried in anatmosphere containing at least 30% relative humidity. It is possiblealthough unnecessary to dip the impregnated paper in water and then dryit in a substantially dry atmosphere.

The condensation polymers of this invention are described and claimed incopending application S. N. 122,844 filed October 21, 1949, nowabandoned.

The polymers there described are prepared by reacting 0.5 to 1.5 mols ofwater with 1 mol of a tetraorgano derivative of orthotitanic acid atroom temperature in an otherwise anhydrous inert organic solvent such asan aromatic or aliphatic hydrocarbon or a halogenated hydrocarbon. Thus,for example, as is shown in Example I of S. N. 122,844, whentetra-n-butyl orthotitanate is dissolved in anhydrous butanol and about0.9 mol of water per mol of orthotitanate is added thereto and theresultant solution is maintained at about 30 C. for 24 hours, there isobtained on vacuum distillation of the solvent a residual transparentliquid polymeric product having a viscosity of about 5-25 poises.

The polymers prepared by the process described in the aforesaidapplication S. N. 122,844 range from liquids to hard solids depending onthe starting derivative of orthotitanic acid and the amount of Waterused. In general, if 0.5 mol of water is used, the product isessentially a dimer. As more water is used, longer straight-chainpolymers are formed until the amount of water becomes greater than 1 molper mol of orthotitanic derivative. At this point a substantial amountof cross-linking takes place, the viscosity of the polymers risesabruptly and the majority of the resulting polymers are solids. Thepolymers to be used as starting materials in accordance with the presentinvention are the straight-chain polymers of tetraorgano derivatives oforthotitanic acid prepared by reacting each mol of the tetraorganoderivative with 0.5-1 mol of water. The

straight-chain polymers are cross-linked by further reaction with water.

Among the titanium organic compounds which may be polymerized to formthe polymers of this invention are esters of ortho titanic acidincluding the methyl, ethyl, propyl, isopropyl, butyl, isobutyl,secondary butyl, tertiary butyl, pentyl, octyl, isooctyl, 2-ethyl hexyl,decyl, lauryl, stearyl, eicosanyl, etc. saturated esters, the allyl,ethallyl, methallyl, crotonyl, oleyl, vinyl, etc. ethylenicallyunsaturated aliphatic esters, the phenyl cresyl, resorcinyl, naphthyl,etc. aromatic esters. The organic groups may contain inorganicsubstituents such as halogen, nitro, amino, sulfone groups, etc.

A second class of titanium organic derivatives which may be used are themixed anhydrides of ortho titanic acid and organic acids. Thesecompounds are sometimes called esters of the organic acid with the orthotitanic acid since the latter is amphoteric in character and may reactas an alcohol. Among the mixed anhydrides which may be used are thetetra-acetate, tetrapropionate, tetrabutyrate, tetra-isobutyrate,tetralaurate, tetrastearate, tetra-oleate, tetrabenzoate,tetranaphthoate, tetracinnamoate, etc. Substituents such as halogen,nitro groups, amino groups, etc. may be present.

A third class of titanium compounds which may be used comprises theamides of ortho titanic acid. These include the reaction products ofortho titanic acid with ethyl amine, methyl amine, butyl amine, decylamine, palmityl amine, oleyl amine, cetyl amine, aniline, benzyl amine,naphthyl amine, etc.

Organic derivatives of metatitanic may also be used to produce thecondensation polymers of this invention.

The condensation polymers range from crystal-clear viscous fluids toWhite waxy solids. They are are soluble in substantially anhydrousorganic solvents including anhydrous alcohols, hydrocarbons, ketones,etc. The polymers may be formed by adding the requisite amount of waterslowly to the anhydrous titanium monomer with constant agitation.However, for ease of Working, the polymerization is preferably carriedout in an anhydrous solvent which may advantageously be an excess of thesolvent used in making the monomer. The polymer prepared in the solventmedium is then used in the form of a solution without freeing it fromthe solvent.

The process of this invention provides a method for treating fabricatedasbestos fibers in the form of paper, rope, batts, cloth, etc. toincrease its wet strength to a remarkable degree and to improve the tearresistance of the paper in both the wet and dry states. The invention isapplicable to woven asbestos sheets as well as to felted asbestos papersuch as Quinterra paper.

It is obvious that variations may be made in the prod- 4 ucts andprocesses of this invention without departing from the spirit and scopethereof as defined by the appended claims.

What is claimed is:

1. A fabricated composition comprising asbestos fibers bonded with thepolymeric water-insensitive reaction product of water and astraight-chain polymer of a tetr'aorgano derivative of orthotitanicacid.

2. A composition as in claim 1 wherein the straightchain polymer is apolymer of a tetra alkyl ester of orthotitanic acid.

3. A composition as in claim 1 wherein the straightchain polymer is apolymer of a mixed anhydridc of an organic acid and orthotitanic acid.

4. A composition as in claim 1 wherein the straightchain polymer is apolymer of a tetra amide of orthotitanic acid.

5. A composition as in claim 1 wherein the straightch'ain polymer is apolymer of tetrabutyl orthotitanate.

6. A process for increasing the wet strength of asbestos paper whichcomprises impregnating the paper with an anhydrous solvent solution of awater-reactive straightchain polymer of a tetraorgano derivative oforthotitanic acid, removing the solvent and exposing the impregnatedpaper to a humid atmosphere in order to condense and insolubilize thepolymer.

7. A process as in claim 6 whereinv the Water-reactive condensationpolymer is a polymer of a tetra alkyl ortho titanate.

8. A. process as in claim 6 wherein the water-reactive condensationpolymer is a polymer of a mixed anhydridc of an organic acid and orthotitanic acid.

9. A process as in claim 6 wherein the water-reactive condensationpolymer is a polymer of a tetra amide of ortho titanic acid.

10. A process as in claim 6 wherein the water-reactive condensationpolymer is a polymer of tetrabutyl ortho titanate.

References Cited in the file of this patent UNITED STATES PATENTS2,466,642 Larsen Apr. 5, 1949 2,546,474 Peyrot et al. Mar. 27, 19512,566,363 Pedlow et al Sept. 4, 1951 FOREIGN PATENTS 125,450 AustraliaSept. 12, 1947 OTHER REFERENCES Journal of Oil 85 Color Chemist Assn.,vol. 3], No. 340, 1948, (pp. 405-410).

6. A PROCESS FOR INCREASING THE WET STRENGTH OF ASBESTOS PAPER WHICHCOMPRISES IMPREGNATING THE PAPER WITH AN ANHYDROUS SOLVENT SOLUTION OF AWATER-REACTIVE STRAIGHTCHAIN POLYMER OF A TETRAORGANO DERIVATIVE OFORTHOTITANIC ACID, REMOVING THE SOLVENT AND EXPOSING THE IMPREGNATEDPAPER TO A HUMID ATMOSPHERE IN ORDER TO CONDENSE AND INSOLUBILIZE THEPOLYMER.